Rehabilitation after knee replacement: stages, limits and warning signs

Rehabilitation after a knee replacement begins almost immediately. The NHS describes walking with the support of a physiotherapist and nurse soon after the operation, and it ties early exercise to long-term strength and movement in the knee rather than treating it as optional.

Most people go home between 1 and 4 days after surgery, according to the same guidance. What that means in practice is that you leave hospital with the new joint still swollen and sore, carrying a set of exercises to do yourself. The physiotherapist who sees you before discharge is usually the person who sets the pace for the next few weeks, so it is worth asking them which exercises matter most and how often to do them.

The NHS describes a stepwise reduction. You start with crutches or a walking frame, move to one crutch when you feel confident, and then to a walking stick. Some people try walking without any aid after about 6 weeks if they are ready.

The wording matters: readiness, not the calendar, decides each step. A limp that settles with a stick is better than a fast move to no support that leaves you favouring the other leg. If you are unsure whether to drop an aid, your physiotherapist can watch you walk and tell you.

Compression stockings are worn at all times for at least 6 weeks and are taken off only to wash. They are there to lower the chance of blood clots, which is one of the complications the NHS lists after knee replacement.

Stitches or clips are normally removed by a nurse at about 10 days. A follow-up appointment is usually arranged for around 6 weeks after the operation, and it is the natural point to ask about driving, kneeling, work and anything that is not progressing as you expected.

The NHS lists a short set of limits for the early months. They are simple, but they are easy to forget once the knee starts to feel better.

• Do not sit with your legs crossed for the first 6 weeks.

• Do not sleep with a pillow under the knee; the aim is to keep the leg able to straighten.

• Do not kneel until your doctor says you can.

• Avoid standing for long stretches.

• Avoid heavy lifting and strenuous household tasks for the first 3 months.

For driving, the NHS says to wait at least 6 weeks after a total knee replacement and at least 3 weeks after a partial replacement, and to confirm with your doctor that you are fit. A useful test is whether you could brake hard in an emergency without hesitation, rather than whether you have reached a particular date. Your insurer may also have its own requirements, so it is sensible to read the policy wording.

A return to work is usually after about 6 to 12 weeks, though the NHS notes it depends on the type of work. A desk job with the leg raised during breaks and a job that involves climbing, kneeling or carrying are not the same recovery, and employers can often arrange a phased return if you ask for one.

The NHS recovery page does not give a timetable for sport, and this guide does not invent one. Return to activity after knee replacement depends on the implant, the surgeon and the type of activity, so the sensible approach is to ask your own team which activities they encourage and which they would advise against in the long term.

For the interim period, the NHS gives two pointers. First, early exercises help long-term strength and movement. Second, full recovery can take several months or longer, so a knee that still aches or swells at the end of a long day in the third or fourth month is not unusual by itself. Persistent worsening is different, and should be reported.

The NHS separates symptoms that need an urgent GP appointment or NHS 111 from those that need an emergency response. Both lists concern infection and blood clots, the two complications that can arise while you are still recovering.

• Throbbing or cramping pain in the leg, a high temperature or chills, oozing or pus from the wound, or increasing redness, tenderness, swelling or pain in the knee: seek an urgent GP appointment or call NHS 111.

• Leg pain and swelling together with difficulty breathing or chest pain: call 999 or go to A&E, as this can signal a clot that has reached the lung.